Corrosion damage is a costly problem for environmentally exposed materials, especially metals. Estimates put the total cost attributed to corrosion at a few percent of the gross domestic product of industrialized countries. In the aerospace industry alone, losses due to corrosion damage exceed $2 Billion per year. Thus, people have attempted many solutions to prevent or reduce the effects of corrosion.
Chemically, metallic corrosion may be described as a coupled electrochemical reaction consisting of anodic metal oxidation and cathodic oxidant reduction. Metallic materials corrode in a variety of gaseous and/or aqueous environments, such as wet air in the atmosphere. Generally, metallic corrosion in its initial stage produces soluble metal ions in water, and then, the metal ions develop into solid corrosion precipitates such as metal oxides and hydroxides.
Corrosion protection may take a variety of forms, such as the introduction of certain elements into corrodible base metal, creating a corrosion-resistant alloy, and/or the addition of a surface coating, such as a chemical conversion coating, a metal plating or a paint. While in use, additional moisture barriers, such as viscous lubricants and/or protectants, may be added to the corrodible surface. Conventional surface coatings for metals may use hexavalent chromium as the active corrosion-inhibiting ingredient. Though effective, environmentally preferred alternatives to hexavalent chromium are being sought. However, hexavalent chromium alternatives typically suffer from several limitations including low corrosion suppression efficacy, poor compatibility with common coating materials, and high cost. Thus there exists a need for improved, and/or more environmentally friendly systems, compositions, and methods for corrosion inhibition.